A Comparative Study on Equilibrium Adsorption of Dyes on Adsorbents Prepared from Coastal Plant, C. equisetifolia Seeds via Green Modification and Activated Carbon

Abstract

Eco-friendly adsorbents were prepared from coastal plant, C. equisetifolia seeds treated with β-cyclodextrin (Rhusorbent) for the removal of dyes. The study was carried out to determine the effectiveness of Rhusorbent to remove common dyes such as malachite green (MG) and neutral red (NR) dyes from aqueous solutions in batch experiments. The commercial activated carbon (AC) was also used in this equilibrium absorption study which includes the effect of adsorbent dosage, initial dye concentration and contact time. The percentage of MG dye removal of about 92.4% and 88.4% was achieved for both Rhusorbent and AC respectively at concentration of 60mg/L and 0.4g absorbent. The equilibrium adsorption of about 91.1% and 79.1% was achieved for both Rhusorbent and AC respectively involving NR dye. The scanning electron micrographs of Rhusorbent show uneven and rough surface prompting evidence for the effective adsorption of MG and NR dyes on the surface of adsorbents. For both adsorption studies, Langmuir and Freundlich isotherm models fitted well the adsorption data involving both Rhusorbent and AC. C. equisetifolia seeds are a potential source for bio-inspired adsorbents for the removal of MG and NR dyes.